Modern medical advancements have significantly broadened the possibilities for sustaining life, even in the face of severe organ failure. While the idea of living without a natural heart might seem extraordinary, it is indeed possible under very specific and controlled medical circumstances. This remarkable feat is achieved through the sophisticated intervention of technology, which can temporarily or, in some cases, for extended periods, take over the heart’s essential functions. Such interventions are typically considered when a person’s own heart is no longer capable of supporting life.
Why the Heart is Essential
The heart functions as a powerful muscular pump, central to the body’s circulatory system. Each day, it beats approximately 100,000 times, propelling about five liters of blood throughout the body. This continuous circulation is crucial for delivering oxygen and vital nutrients to every cell and tissue. Without this constant supply, organs and muscles cannot function properly, leading to systemic failure.
Beyond delivering essential substances, the heart also plays a critical role in removing waste products. Blood collects carbon dioxide and other metabolic byproducts from the tissues, transporting them back to the lungs and kidneys for elimination. The heart’s rhythmic pumping action also helps maintain blood pressure, ensuring adequate blood flow to all parts of the body. The coordinated effort of the heart and the vast network of blood vessels ensures that the body’s complex systems receive the support they need to sustain life.
How Medical Technology Replaces Heart Function
When a natural heart can no longer effectively pump blood, medical technology can intervene using devices like Ventricular Assist Devices (VADs) and Total Artificial Hearts (TAHs). These mechanical pumps are designed to either support or completely replace the heart’s pumping action. VADs are commonly used to assist a failing ventricle, with Left Ventricular Assist Devices (LVADs) being the most prevalent as they support the heart’s main pumping chamber responsible for delivering oxygen-rich blood to the body. These devices reduce the heart’s workload, which can prolong life and alleviate symptoms such as fatigue and breathlessness.
VADs consist of an implanted pump, often connected to an external control unit and battery pack worn by the patient. The pump draws blood from a heart chamber, typically the left ventricle, and propels it into the aorta, mimicking the heart’s natural pumping action. VADs serve various purposes, including acting as a “bridge to transplant,” sustaining patients while they await a donor heart, or as “destination therapy” for those ineligible for a transplant, providing long-term support. Some VADs also offer a “bridge to recovery,” allowing the heart to heal, after which the device might be removed.
For more severe cases where both lower heart chambers are failing, a Total Artificial Heart (TAH) may be implanted. A TAH completely replaces the heart’s damaged ventricles and valves, taking over the entire pumping function. The SynCardia Total Artificial Heart is one such device, which uses an external pneumatic driver to control the pumping action via tubes connected through the skin. This device, like VADs, is primarily used as a temporary measure to keep patients alive until a heart transplant becomes available, especially when VADs are not a suitable option.
Life Sustained by Artificial Means
Living with artificial heart support involves significant physiological adaptations and practical considerations for individuals. Many modern VADs, particularly LVADs, create a continuous flow of blood rather than the pulsatile flow of a natural heartbeat. Patients with these continuous-flow devices may have no palpable pulse or measurable blood pressure, a sensation that can initially be unusual for them. While the body generally adapts to this non-pulsatile circulation, some research explores the long-term effects of this different flow pattern on organs and vessels.
Patients with VADs or TAHs manage their devices daily, which includes caring for the driveline site where the device connects to external components to prevent infection. They also manage power sources, typically battery packs that require regular recharging. These external components can affect mobility and require careful planning for daily activities, including showering. Despite these adjustments, many patients report significant improvements in energy levels and quality of life, allowing them to engage in activities they could not perform before the device implantation. Some individuals feel a renewed sense of optimism and a “second chance” at life.
Challenges and Limitations of Heart Support
While mechanical circulatory support devices offer a lifeline for individuals with severe heart failure, they come with significant challenges and limitations. One major concern is the risk of complications such as infection, particularly at the driveline exit site where external components connect to the body. The presence of foreign material in the body also increases the likelihood of blood clots forming, which can lead to serious events like stroke. Managing this risk requires lifelong anticoagulant therapy, which in turn increases the risk of bleeding.
Device malfunction is another potential issue, necessitating ongoing monitoring and possible reoperation. The size of Total Artificial Hearts can be a limiting factor, as patients need sufficient chest cavity space for implantation. Furthermore, these devices can be noisy, producing a “whirring sound” that patients may notice. While these technologies significantly extend life and improve well-being for many, they are not without their burdens, including the need for continuous medical care, potential restrictions on certain physical activities, and the psychological impact of living with a life-sustaining machine.